For example, an Advanced Television Systems Committee (ATSC) 3.0, one of next-generation terrestrial broadcasting standards, determines use of not Transport Stream (TS) packets but UDP/IP, that is, IP packets including UDP packets, for data transmission. The use of the IP packets also in a broadcast system other than ATSC 3.0 is expected in the future.
By the way, the IP packet includes various pieces of information in a header, and this causes a large overhead. Therefore, as a technique to compress the header in the IP packet for effective transmission of the IP packet, there has been provided a Robust Header Compression (RoHC) specified by an Internet Engineering Task Force (IETF).
In the RoHC, the IP packet including all information in the header (hereinafter also referred to as a complete IP packet) is transmitted. Regarding a header in the subsequent IP packet, information different from that in the header in the previous complete IP packet is transmitted.
Like the RoHC, the compression technique of the header in the IP packet that transmits the complete IP packet and then transmits the IP packet with the header including the information different from that in the header in the complete IP packet is hereinafter also referred to as a differential compression method.
For example, in an advanced broadcast satellite (BS), the differential compression method has been specified as a technique to compress the header in the IP packet (Non-Patent Document 1).